1. Field of the Invention
The present invention relates to a method for manufacturing an ink jet recording head, and an ink jet recording head manufactured by such method of manufacture. More particularly, the invention relates to a method for manufacturing an ink jet recording head capable of forming the head with inorganic material without depending on the use of organic resin material. The invention is also intended to materialize the provision of an ink jet recording head manufactured by such method of manufacture.
2. Related Background Art
Conventionally, the ink discharge mechanism of an ink jet recording head to which the ink jet recording method is applicable has in general comprised discharge ports for discharging ink; the liquid chamber which retains ink to be supplied to the discharge ports; the ink flow paths which are communicated with the discharge ports and the liquid chamber; each of energy generating elements arranged a part of each of the ink flow paths for generating energy to discharge ink; and an ink supply port through which ink is supplied from outside to the liquid chamber.
For the processing of the ink flow paths and ink discharge ports, among those described above, which require minute structures and high precision, it has been generally practiced in recent years to perform the patterning irradiation of high energy ultraviolet laser, such as excimer laser, onto the resin material for the formation of an intended structure, and then, to execute sublimate etching therefor by the application of the photo-chemical reaction for cutting covalent bond of carbon atom. Here, this method is called collectively an ablation processing method in a sense of being executable without the intervention of providing liquid phase.
Also, as another method, it has been proposed to form ink flow paths by use of the wet etching which acts upon a material of ultraviolet decay type. In this method, the photolithographic process is used for processing an IC chip having a pressure generating source thereon with two kinds of resin materials, that is, the one that decays by the irradiation of ultraviolet rays, and the other that does not absorb ultraviolet rays, and then, a pattern that corresponds to the configuration of ink flow paths is made by use of the material of ultraviolet decay type, while the other side thereof is provided with an overcoated layer for the formation of ink discharge ports. Then, after the ink discharge ports have been etched, the material of ultraviolet decay type, which is processed in the form of the ink flow paths by the irradiation of ultraviolet rays, is low molecularly quantified to be conditioned so that solvent can be eluted.
However, although it is possible to process resin material by use of these conventional methods, it is difficult to process materials other than resin, thus necessitating use of a processible resin material for the formation of an intended structure. As a result, processing should be made dependent on the resin material despite such properties thereof as lower mechanical strength, easier surface spoilage, heating limit due to lower glass transition point, and the higher thermal expansion and moisture absorption coefficients which may result in easier generation of inner stress due to environmental temperatures or humidities, among some others. These may ensue in easier deformation or some other characteristic problems of resin material.
Particularly in case of an ink jet recording head, it is extremely difficult for the resin material to meet such requirements as higher durability and higher reliability so as to prevent the ink discharge surface from being spoiled due to chipping thereof and peeling off of water-repellent agent or inferior capability to maintain water-repellency, or so as to prevent it from the breakage of the bonded faces due to the generation of inner stress.
Now, therefore, the present invention is designed with a view to solving these problems encountered in the conventional art. It is an object of the invention to provide a method for manufacturing a highly durable and reliable ink jet recording head formed with inorganic material without depending on use of organic material so as to make it hard, and not easily damaged, and also, to enable the ink discharge surface thereof not to be easily spoiled, and the bonded faces not easily broken due to the inner stress, either. It is also an object of the invention to provide an ink jet recording head manufactured by such method of manufacture.
In order to achieve these objects, the invention provides a method for manufacturing an ink jet recording head, as well as an ink jet recording head manufacture by such method of manufacture, which are structured as described in the following paragraphs (1) to (18).
(1) A method for manufacturing an ink jet head, which is provided with an ink discharge mechanism structured to include at least an ink discharge port and an ink flow path on a member having a pressure generating source thereon, the pressure generating source giving pressure to ink being in contact therewith so as to propagate the pressure to the ink discharge port for discharging an ink droplet, and enabling the ink droplets to adhere to a recording medium, comprises the steps of forming in a thick film laminating step a patterning layer corresponding to the configuration of ink flow path on a member provided with the pressure generating source, and overcoating inorganic material layer on the pattering layer to form ink discharge surface; irradiating the patterned image of predetermined ink discharge port configuration by laser capable of completing sublimate ablation process before the laser beam is dispersed in a work piece as thermal energy;
subsequently, executing the sublimate ablation process on ink discharge ports almost simultaneously from the inorganic material layer on the ink discharge side up to the interior of the thickness of the patterning layer corresponding to the configuration of ink flow path; and removing the patterning layer corresponding to the configuration of the ink flow path after processing the ink discharge port to manufacture an ink jet recording head.
(2) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the laser is the laser continuously emitting from a laser oscillator photopulse (optical pulse) having large spatial and temporal energy concentration in pulse emission period of one picosecond or less, and the laser beam emitted from the laser oscillator is irradiated on a specifically patterned image with a predetermined energy concentration and a predetermined number of aperture (NA) for the execution of sublimate ablation almost simultaneously from the inorganic material layer on the ink discharge side up to the interior of the thickness of the patterning layer corresponding to the configuration of the ink flow paths.
(3) A method for manufacturing an ink jet recording head referred to in the paragraph (1) or (2), wherein the energy concentration of laser beams satisfies the conditional expression of
(axc3x97nxc3x97E)/t greater than 13xc3x97106[W/cm2]
where a is the absorptivity of the laser wave length irradiated to a work piece material; n is the number of aperture of the optical system on the work piece side to project the processing pattern to the work piece; E (unit [J/cm2/pulse]) is energy per unit area of the laser beam irradiated onto the work piece material per unit oscillating pulse period; and t (unit [sec]) is the width of laser oscillation pulse period.
(4) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the laser oscillator is a laser oscillator provided with a spatial compression device for light propagation.
(5) A method for manufacturing an ink jet recording head referred to in the paragraph (4), wherein the spatial compression device for light propagation comprises chirping pulse generating means; and vertical mode synchronizing means utilizing light wavelength dispersion characteristics.
(6) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the formation of the patterning layer corresponding to the configuration of the ink flow path is made by means of photolithographic process.
(7) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the patterning layer corresponding to the configuration of the ink flow paths is formed by metallic material.
(8) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the overcoating of the inorganic material layer for the formation of the ink discharge surface is formed by means of CVD or other chemical deposition development method.
(9) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the overcoating of the inorganic material layer for the formation of the ink discharge surface is formed by means of PVD or plasma flame or other physical deposition development method.
(10) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein subsequent to overcoating the inorganic material layer for the formation of the ink discharge surface, the ink discharge surface is polished or grounded for processing for smoothing the ink discharge surface.
(11) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein subsequent to overcoating the inorganic material layer for the formation of the ink discharge surface, the ink discharge surface is coated with water-repellent agent and thermally cured.
(12) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the inorganic material layer for the formation of the ink discharge surface is formed by dielectric or ceramic material.
(13) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the removal of the patterning layer corresponding to the configuration of the ink flow paths is performed by means of wet etching or other chemical etching.
(14) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the method for manufacturing an ink jet recording head is the method of manufacture of an ink jet recording head of plane discharge type having the pressure generating source arranged above the ink discharge port, and the ink discharge port is processed by sublimate ablation almost simultaneously from the inorganic material layer on the ink discharge side up to the interior of the thickness of the patterning layer corresponding to the configuration of the ink flow path.
(15) A method for manufacturing an ink jet recording head referred to in the paragraph (1), wherein the method for manufacturing an ink jet recording head is the method of manufacture of an ink jet recording head of edge shooter type comprising an ink liquid chamber for supplying ink to the ink discharge port, an ink flow path communicated with the ink liquid chamber, an ink supply port for supplying ink from the outside to the ink liquid chamber, and an energy generating element provided for part of the ink flow path forming the pressure generating source, and the ink discharge formation surface is formed by removing the edge face of the inorganic material layer by cutting or grinding or polishing from the edge face side of the patterning layer overcoated on the edge face and upper face of the inorganic material layer so as to provide a specific thickness thereof, and then, the ink discharge port is processed on the ink discharge port formation surface by sublimate ablation almost simultaneously from the ink discharge side to the edge face of the patterning layer up to the interior thereof.
(16) An ink jet recording head provided with an ink discharge mechanism structured to include at least an ink discharge port and an ink flow path on a member having a pressure generating source thereon, the pressure generating source giving pressure to ink being in contact therewith so as to propagate the pressure to the ink discharge port for discharging an ink droplet, and enabling the ink droplets to adhere to a recording medium, wherein the ink jet recording head is manufactured by a method for manufacturing an ink jet recording head referred to in either one of the paragraphs (1) to (15).
(17) An ink jet recording head referred to in the paragraph (16), wherein the ink jet recording head is plane discharge type having the ink discharge port arranged above the pressure generating source.
(18) An ink jet recording head referred to in the paragraph (16), wherein the ink jet recording head is edge shooter type having said ink discharge port on the edge side of said inorganic material layer.
As described above, in accordance with the present invention, it is possible to form the structural members, such as the ink discharge surface of an ink jet recording head, with dielectric or ceramic or other inorganic. material without depending on organic resin material. Therefore, not only it becomes possible to form an ink jet surface or the like which is hard and not easily damaged, but also, to burn and coat water-repellent agent, because heat treatment can be given at a temperature of as high as approximately 500xc2x0 C. The durability of the water-repellent film, and the durability of the ink discharge surface or the like can be enhanced significantly. As a result, materials can be selected more freely in consideration of thermal expansion, moisture expansion, and other problems. Then, with an optimal designing, it becomes possible to manufacture a highly durably and reliable ink jet recording head.